The popularity of mobile digital devices, such as smart phones, personal data assistants, digital cameras, etc., has increased dramatically in recent years. As a result, a typical device user routinely carries vast amounts of digital information in their pockets. In addition, access to the Internet is rapidly becoming ubiquitous, increasing the amount of information at a user's fingertips dramatically. Much of this information is in the form of media, such as web pages, videos, live television, photographs, books, and the like, which is meant for display. Unfortunately, the small form-factor of many mobile digital devices, while enabling easy mobility, does not lend itself well to the display of the stored information. As a result, portable projectors (often referred to as “pico-projectors”) that attach to the mobile devices and project the information onto a convenient surface have become increasingly attractive. Pico-projectors have found use in many applications, including heads-up displays in cars and planes, business presentations, and entertainment.
One popular type of projector is based on the projection of laser light. Such projectors are enabled, in part, by the development of miniature solid-state lasers. In order to project color images, light signals from multiple lasers (typically emitting red, green, and blue light) are combined using free-space optics to form a composite light beam that is then scanned over the intended display region. Unfortunately, widespread adoption of such projectors remains slow due to their relatively large size.
Another available projector type is based on liquid crystals (LC's). LC-based projectors either project an image through a liquid-crystal display, or construct the image by reflection onto a liquid-crystal-on-silicon (LCoS) display using light bulbs or LEDs as light sources.
Unfortunately, currently available pico-projectors are still relatively large, complex, and expensive. Further, projectors based on free-space optical systems require labor-intensive assembly. As a result, it is difficult to manufacture such projectors in high volume at low cost.